Electrode fuse protector



June 18, 1968 s. M. DE CORSO ELECTRODE FUSE PROTECTOR Filed March 7,1967 FIG.2

R o T N v E 6 V 2 W 4 G F O 3 4 G 9 F 0 2 M 9 3 3 ll G r A 3 N IN IlllllS I I1 1 1| I ll .1 ll A Illll I I w 4 Y F 8 3 2 3 3 E I 4 2 E 4 N W Serdfino M. DeCorso ATTORNEY United States Patent 3,389,209 ELECTRODE FUSEPROTECTOR Serafino M. De Corso, Media, Pa., assignor to Westing houseElectric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania 13Claims. (Cl. 13-18) N ABSTRACT on THEDISCLOSURE Background of theinvention This invention relates to improvements in fuses, and moreparticularly to a fuse for protecting an electrode used in an arcfurnace.

In the operation of non-consumable electrodes in an arc furnace, theterm non-consumable as employed herein signifying an electrode having afluid-cooled arcing tip with a passageway for cooling fluid near thearcing surface and a field coil in the tip for setting up a magneticfield to rotate the arc, one of the most severe operating conditionsoccurs during the short interval when the electrode is starting an areon a cold scrap charge. Standard furnace regulation is such that until asecond electrode approaches within arcing distance of the scrap noarcing action occurs at the first electrode. Therefore, the travel ofthe first electrode is regulated by voltage indication between theelectrode and the scrap or bath until arcing commences. This means thatthe first electrode will be very close to sizeable scrap pieces and maybe in actual direct contact with the scrap.

Summary of the invention In summary, the fuse of my invention provides aphysical barrier of diamagnetic material between the electrode tip orarcing surface, and the scrap. My invention includes severalmodifications including one in which the fuse is positioned by hand, anda second one in which the fuse is fed or moved into position down acentrally located axial aperture in the electrode.

Accordingly, an object of the invention is to provide a new and improvedelectrode fuse.

A further object is to provide a new and improved electrode fusecomposed of diamagnetic material.

A still further object is to provide a new and improved electrode fusewhich may be inserted through the central aperture of the electrode.

Description of the preferred embodiments In FIG. 1, the electrode isgenerally designated 11 having an electrode face member or electrode tipshown at 12 and forming an arcing surface. The fuse generally designated13 is seen to be interposed between the electrode tip 12 and the scrapcharge indicated at 14. The fuse is generally seen to include a flangeportion 16 of a diameter sufficiently great to insure that no portion ofthe electrode tip comes in direct contact with scrap, and a hub orcylindrical portion 17 which extends up into the central aperture 19 ofthe annular arcing tip member 12. This hub or cylindrical portion 17 ofthe fuse may be sufiiciently long if desired to extend into the centralpassageway 20 of the electrode.

As previously stated the fuse generally designated 13 may be composed ofdiamagnetic material. Suitable materials are carbon, or graphite, or acarbon-graphite mixture. The fuse in FIG. '1 is inserted by hand intothe end of the electrode before the electrode is lowered into thefurnace and is maintained in place by pressure contact at thecylindrical portion 17 with the adjacent wall of the tip 12 and/or theadjacent wall of the central aperture 20 through the electrode.

If desired, suitable clips extending from the tip and projecting overthe flange portion may be added to additionally secure the fuse inplace, these not being shown for convenience of illustration.

In operation current coduction is first from the electrode face or tipmember through the fuse to the scrap until the fuse is expended at whichtime arcing occurs from the electrode tip 12 to the scrap 14'.

In FIG. 2 a further embodiment of the fuse is shown generally designated22 and generally being of a solid cylindrical construction. The fuse 22is inserted by hand into the end of the electrode and is held inposition by interference fit, and an are 24 is shown taking place fromfuse 22 to scrap 14. The fuse 22 is rapidly expended on consumed andafter a short time interval the arc takes place directly from theelectrode tip 12 to the scrap 14.

Particular reference is now made to FIG. 4- which shows anotherembodiment, or modification, of a fuse similar to that of fuse 22 exceptthat the fuse element 26 of FIG. 4 is hollow and is cylindrical inshape, the operation being similar to that of the fuse in FIG. 2.

Particular reference is made now to FIG. 3. An elongated fuse 28 extendsthe entire length of the central aperture 29 of electrode 30, and theend portion 31 of the fuse extends beyond the arcing surface 32 of theelectrode. Arc 33 is seen taking place from the end 31 of the fuse tothe scrap 14, and it will be understood that the extended end portion ofthe fuse is rapidly consumed by the action of the arc, and after a shortperiod of operation the arc transfers to the arcing surface 32 of theelectrode and that the arc thereafter takes place from the electrode tothe scrap.

The invention includes a feeding device having leads 41 and 42 locatedat the top of the electrode in FIG. 3 to automatically feed fuse upon adead short indication of electrode to scrap.

The automatic fuse feeding means 40 may be dispensed with, if desired.

The foregoing written description and drawings it will be understood areillustrative only and are not to be interpreted in a limiting sense.

I claimas my invention:

1. A fuse for an electrode to be used in an arc furnace, the fuse beingcomposed of diamagnetic material, the fuse extending beyond the arcingsurface of the electrode and being interposed between the electrode andthe scrap of the furnace whereby when a current path is first providedthrough the electrode, an arc first takes place from the fuse to the.scrap, the arcrapidly consuming the material of the fuse, the are aftera short time interval being transferred to the electrode and takingplace between the electrode and the scrap.

2. A fuse according to claim 1 including a flange portion having anouter diameter at least as great as the outer diameter of the arcingsurface of the electrode and a cylindrical portion adapted to beinserted into the central aperture of the electrode and to be held infrictional engagement therein.

3. A fuse according to claim 2 in which the cylindrical portion isadditionally described as being sufliciently long to extend into thecentral aperture of the electrode.

4. A fuse according to claim 1 in which the fuse is additionallycharacterized as being composed of carbon.

5. A fuse according to claim 1 additionally characterized as beingcomposed of graphite.

'6. The fuse according to claim 1 additionally characterized as beingcomposed of a carbon-graphite mixture.

7. A fuse according to claim 1 additionally characterized as beingcylindrical in shape.

'8. A fuse according to claim 7 additionally charac- 20 electrode thatthe end of the fuse adjacent the arcing surface of the electrode extendsbeyond the arcing surface, an arc first taking place from the fuse tothe scrap when the arc is started, the material of which the fuse iscomposed being rapidly consumed until the arc transfers to the electrodeand takes place between the electrode and the scrap.

10. A fuse according to claim 9 composed of carbon.

11. A fuse according to claim 9 composed of graphite.

12. A fuse according to claim 9 composed of a carbongraphite mixture.

13. A fuse according to claim 9 including in addition fuse feeding meanslocated at the top of the electrode to automatically feed the fuse upona dead short indication of electrode to scrap.

References Cited UNITED STATES PATENTS 2,516,037 7/1950 Williams 219-1313,030,490 4/1962 Reed 21975 3,238,349 3/1966 Anderson 219-75 BERNARD A.GILHEANY, Primary Examiner.

25 H. B. GILSON, Assistant Examiner.

